Telegram

Approximation Problems for RBI Assistant 2021, CET, SBI Clerk, IBPS Clerk, LIC at Smartkeeda

Directions: What value will come in place of question mark (?) in the following questions: (You are not expected to calculate the exact value)
1
38.98 × √(195.98) ÷ 41.87 = ?1/2 – 84.03 × 7.06 ÷ √(441.02)
» Explain it
C
38.98 × √(195.98) ÷ 41.87 = ?1/2 – 84.03 × 7.06 ÷ √(441.02)

≈ 39 × √196 ÷ 42 = ?1/2 – 84 × 7 ÷ √441
 
39 × 14 ÷ 42 = ?1/2 – 84 × 7 ÷ 21
 
13 = ?1/2 – 28
 
13 + 28 = ?1/2
 
41 = ?1/2
 
? = 1681 ≈ 1680

Hence, option C is correct.
 
2
18.006 × ? × 27.987 + 28% of 640 + 25% of 830 = 8954.784
» Explain it
A
18.006 × ? × 27.987 + 28% of 640 + 25% of 830 = 8954.784

18 × 28 ×  ? + 179.2 + 207.5 = 8954.784

504 ×  ? = 8954.784 – 386.7

504 ×  ? = 8568.084
 
? = (8568.084 / 504)

? = 17

Hence, option A is correct.

3
{(156.8 × 5 – ∛ 10648) / (14 × 12 + 132 + (?)2} = 2
» Explain it
A
{(156.8 × 5 – ∛ 10648) / (14 × 12 + 132 + (?)2} = 2

{(784 – 22) / (168 + 132 + (?)2)} = 2

{762 / (300 + (?)2} = 2

762 = 2 × (300 + (?)2)

762 = 600 + 2 × (?)2

2 × (?)2 = 162

(?)2 = 81

(?)2 = 92

? = 9

Hence, option A is correct.

4
[{(5.6 / 3.8) × (11.4 / 8.4)} / (35.5 / 5) × (25.5 / 5)] % of 10863

» Explain it
D
[{(5.6 / 3.8) × (11.4 / 8.4)} / (35.5 / 5) × (25.5 / 5)] % of 10863

{(5.6 × 11.4 × 5 × 5) / (3.8 × 8.4 × 35.5 × 25.5)} % of 10863

{(2.8 × 2 × 3.8 × 3 × 5 × 5) / (3.8 × 2.8 × 3 × 7.1 × 5 × 5.1 ×5)} % of 10863

{ 2 / ( 7.1 × 5.1)} % of 10863

(200 / 3621) % of 10863

10863 × (200 / 3621) × (1 / 100)

10863 × (2 / 3621)

(3 × 3621) × (2 / 3621)

{(3 × 3621 ×2 ) / 3621}

3 × 2 = 6

Hence, option D is correct.
 
5
9723.88 ÷ 67.94 + 47.08 × 4.02/ 6.13 = ?2 – 22
» Explain it
D
9723.88 ÷ 67.94 + 47.08 × 4.02/ 6.13 = ?2 – 22

?2 = 9724 ÷ 68 + 47 × 4/ 6 + 22

?2 = 143 + 31.33 + 22

?2 = 165 + 31

?2 = 196

? = 14

Hence, option D is correct.